Pressure-actuated circuit breaker



Oct. 11, 1966 H. L. SMITH PRESSURE-ACTUATED CIRCUIT BREAKER 2 Sheets-Sheet 1 Filed Sept. 14, 1964 INVENTOR: ZZf V/WA O ,f/w/r/l 2 Q z; TTORNEY United States Patent 3,278,704 PRESSURE-ACTUATED CIRCUIT BREAKER Henry Leo Smith, Rte. 4, Barren Plains, Springfield, Tenn. Filed Sept. 14, 1964, Ser. No. 396,183 4 Claims. (Cl. 200-83) This invention relates to a pressure-actuated circuit breaker, and more particularly, to a circuit breaker for automatically opening an electrical circuit in a system controlling fluid flow, when the fluid pressure is reduced below a predetermined value.

One object of this invention is to provide a pressureactuated circuit breaker particularly adapted for use in a water system for stopping the pump when the water pressure falls below a predetenmined value.

Another object of this invention is to provide a pressure-actuated circuit breaker adapted to stop a pump before it loses its prime and before any water lubricated parts in the pump are damaged.

Another object of this invention is to provide a pressure-actuated circuit breaker adapted to open a circuit when the pressure in a fiuid flow system is too low, and is further provided with manual means for re-closing the circuit even while the pressure is too low.

A further object of this invention is to provide a pressure-acuated circuit breaker for automatically stopping a pump when the water pressure drops below a predetermined value, and a manually operated device for restarting the pump at pressures below the predetermined value.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings, wherein:

FIG. 1 is a schematic view of the invention employed in a Water system for controlling an electric pump;

FIG. 2 is a perspective view of the circuit breaker with parts broken away;

FIG. 3 is a section of the circuit breaker taken along the line 3-3 of FIG. 4;

FIG. 4 is a section taken along the line 44 of FIG. 3; and

FIG. 5 is a section taken along the line 55 of FIG 3.

Referring now to the drawings in more detail, FIG. 1 discloses a pump 10, driven by an electric motor 11 for pumping water 12 through a line or pipe 13 into a tank 14. The tank 14 is shown as having a head of compressed air 15 for exerting pressure upon the Water 12. As the water 12 is drawn olf through the outlet line 17, the pressure of the air 15 and the water 12 is gradually reduced. The pressure regulating control device 19 in the electrical circuit 20 is designed to stop the motor 11 and shut-off the pump when the pressure in the line 13 exceeds a predetermined maximum value such as 40 p.s.i., and for starting the motor 11 to operate the pump 10 when the pressure in the line 13 drops below a predetermined minimum value, such as 20 p.s.i. The water system and controls thus far described are conventional, and Widely used in rural areas where water is supplied to homes from wells.

It is the purpose of this invention to provide a novel pressure-actuated circut breaker 22 designed to open the electrical circuit 20 to stop the motor Ill and shut 0d the pump 10 when the pressure in the line 13 drops below the minimum operative pressure of the control device 19. In a conventional system where the cut-in pressure is 20 p.s.i. and the cutout pressure is 40 p.s.i., the device 22 is designed preferably to open the circuit 20 when the pressure is reduced approximately 10 p.s.i. below the minimum cutting pressure of the device 19. For example, it is conceivable that conditions could arise in the system Where the pump 10 will continue to run indefinitely With- "ice out building up the pressure in the tank 14. Where the water is drawn from a well, the well could run dry with the pump 10 still operating until it is burned out and has damaged all its water lubricated parts. It is one of the purposes of this invention to prevent such occurrences by stopping the pump at these damaging low-Water pressures.

As best disclosed in FIGS. 25, the circuit breaker 22 comprises a housing or casing 24 having a pressure chamber 25 in the bottom thereof. A flexible diaphraghm or membrane 26 is secured in the chamber 25 to expand upwardly upon an increase of pressure in the chamber 25 and to collapse downwardly upon a decrease in pressure. The chamber 25 communicates with the water line 13 through the passage 27 and the pipe 28.

Firmly secured to and adapted to reciprocate axially up and down in the housing 24 is a stem 30. The stem 30 is guided axially through a lower aperture or bearing 31 and an upper aperture or bearing 32 in the housing 24.

A spring 34 is coiled around the upper portion of the stem 30 and extends between a pair of cupped spring retainers 35 and 36 through which the stem 30 is adapted to freely reciprocate. However, the upper spring retainer 35 is adapted to bear against the top wall of the casing 24 and the bottom retainer 36 is adapted to bear against a nut threadedly engaging a portion of the stem 30 for adjustment of the strength of the spring 34.

Spaced below the adjusting nut 37 is an enlarged annular cam or shoulder 40, fixed to and coaxial with the stem 30, and having a slightly greater diameter. The shoulder 40 has a fiat bottom surface 41 adapted to operatively engage and actuate the switch lever 42. The lever 42 includes two sections or arms 43 and 44. The first lever section 43 is pivotally mounted at one end on the casing 24 about a pivot pin 45 whose axis is normal to the axis of the stem 30. The other end of the first lever section 43 carries a movable electrical switch contact bridge or bar 47, which is adapted to swing in a vertical plane with the lever section 43. One end of the second lever section 44 is pivotally connected to the first lever section 43 by a pin 49 whose axis is normal to the axis of the pivot pin 45, so that the second lever section is adapted to swing in a plane normal to the pivotal plane of the lever section 43. In its normal operative position, the second lever section 44 extends across and against the stem 30 as best disclosed in FIG. 5, and beneath and in engagement with the fiat shoulder surface 41.

The free end .of the lever section 44 is connected to the lower end of the switch spring 50, the upper end of which is connected to the top wall of the housing 24. The switch spring 50 is biased to pivot the lever 42 about the pivot pin 45 upwardly.

The free end of the lever section 44 is also connected to one end of a trigger spring 52, the other end of which is secured to the front wall of the housing 24 and normally biases the lever section 44 toward engagement with the stem 30.

A pair of switch contacts 54 and 55 are stationarily mounted on a bracket 56 fixed to the side wall of the housing 24, to position the contacts 54 and 55 in the pivotal path of the bridge 47. The contacts 54 and 55 are connected to leads 57 and 58 respectively, in the circuit 20. Thus, as long as the pressure in chamber 25 is above the predetermined actuating pressure, such as 10 p.s.i., then the position of the stem 30, shoulder 40 and lever 42 is such that the bridge 47 is engaging the contacts 54 and 55 to close the circuit '20 and maintain the normal operation of the pump 10, as disclosed in phantom in FIG. 4. When the pressure in the water line 13 has dropped below the predetermined actuating pressure of the circuit breaker 22, the pressure is transmitted to the chamber 25 causing the diaphragm 26, stem 30 and shoulder 40 to drop to the solid line position disclosed in FIGS. 4 and 5. The depression of the shoulder 40 pivots the entire lever 42 including the bridge 47 downwardly to dis-engage the contacts 54 and 55 to open the circuit 20 and stop the motor 10.

In the event that it is desired to operate the pump even though the pressure in the line 12 is below the actuating pressure, an overrule plunger 60, reciprocably mounted in the bearing 61 in the front wall of the housing 24 is depressed. The operative end 62 is adapted to engage the front edge of the lever section 44, as disclosed in FIGS. 3 and 4. A manual button or handle 63 is formed on the opposite end of the plunger 60 outside the housing, and is normally biased outwardly by the spring 64. When the button 63 is depressed or pushed against the housing 24, the operative end 62 of the plunger 60 thrusts the lever section 44 pivotally about the pin 49, away from the stem 30 and outwardly from beneath the shoulder 40, and against the tension of the spring 52. When the lever section 44 clears the shoulder 40, the switch spring 50 pulls the lever 42 upwardly until the bridge 47 again engages the contacts 54 and 55 to close the circuit 20. When the plunger button 63 is released, the lever section 44 is biased against the side of the shoulder 40 by the trigger spring 52, but is no longer subject to the control of the shoulder 40 or the pressure membrane 26.

Of course, when the pressure in water line 13 builds up again, the membrane 26 gradually thrusts the stem 30 and shoulder 40 upwardly. When the fiat shoulder surface 41 rises above the top of the lever section 44, the trigger spring 52 will again retract the lever section 44 beneath the shoulder 40 to render the circuit breaker 22 automatic and subject to the pressure in the line 13.

Although this circuit breaker 22 is particularly designed and disclosed for use with a water pump and a water circulating system, it will be understood that the circuit breaker 22 may be employed with other types of fluid pressure control systems, such as a safety device for a water heater or an air compressor.

It will be apparent to those skilled in the art that various changes may be made in the invention, without departing from the spirit and scope thereof, and therefore, the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. A circuit breaker comprising:

(a) a housing,

(b) a stern mounted for longitudinal axial movement in said housing,

(c) a pressure responsive member connected to one end of said stern for thrusting said stem toward the opposite end upon an increase in pressure,

((1) spring means biasing said stern toward said one end,

(e) an actuating shoulder fixed on said stem,

(f) a lever,

(g) first means pivotally mounting said lever on said housing transversely of said stem 80 that said lever normally extends across said stern and in engagement for axial movement with said shoulder,

(h) spring means biasing said lever into engagement with said shoulder,

(i) a movable electrical contact carried by said lever,

(j) a stationary electrical contact mounted on said housing in the pivotal path of and normally engaging said movable contact,

(k) said contacts being dis-engaged when said pressure responsive member senses a pressure below a predetermined value,

(1) second means connected to said first means and mounting said lever to pivot transversely of said stem toward and away from engagement with said shoulder, and

(In) means mounted in said housing movable to thrust said lever transversely away from engagement with said shoulder to permit said contacts to engage regardless of the value of said pressure.

2. The invention according to claim 1 in which said first means comprises a lever section forming an extension of said lever, said movable contact being mounted on said lever section, said lever section being mounted on said housing to pivot about a first axis normal to the axis of said stem, said second means comprising a second pivotal axis normal to said first axis.

3. The invention according to claim 1 in which said movable means to thrust said lever comprises a plunger rod axially movable through said housing and having an end engaging said lever, said plunger rod being mounted to reciprocate in the plane of transverse pivotal movement of said lever, and spring means biasing said lever toward said stem.

4. The invention according to claim 3 in which the spring means biasing said lever into engagement with said shoulder comprises a first spring having one end connected to said housing and the other end connected to said lever to bias said lever axially of said stem toward said opposite end, and said spring means biasing said lever toward said stem comprises a second spring having one end connected to said housing transversely of said stem and the other end connected to said lever.

References Cited by the Examiner UNITED STATES PATENTS 2,447,894 8/1948 Bauman 200-83 X 2,794,088 5/1957 Ostby ZOO-83 References Cited by the Applicant UNITED STATES PATENTS 398,069 2/1889 Nagle. 552,803 1/ 1896 Williams. 671,244 4/ 1901 Stewart. 953,028 3/ 1910 Griscom.

2,050,113 8/1936 Miner. 2,061,270 11/1936 Carlson. 2,226,325 12/ 1940 Sandford. 2,680,168 6/ 1954 Murphy. 2,767,277 10/1956 Wirth.

BERNARD A. GILHEANY, Primary Examiner.

G. MAIER, Assistant Examiner. 

1. A CIRCUIT BREAKER COMPRISING: (A) A HOUSING, (B) A STEM MOUNTED FOR LONGITUDINAL AXIAL MOVEMENT IN SAID HOUSING, (C) A PRESSURE RESPONSIVE MEMBER CONNECTED TO ONE END OF SAID STEM FOR THRUSTING SAID STEM TOWARD THE OPPOSITE END UPON AN INCREASE IN PRESSURE, (D) SPRING MEANS BIASING SAID STEM TOWARD SAID ONE END, (E) AN ACTUATING SHOULDER FIXED ON SAID STEM, (F) A LEVER, (G) FIRST MEANS PIVOTALLY MOUNTING SAID LEVER ON SAID HOUSING TRANSVERSELY OF SAID STEM SO THAT SAID LEVER NORMALLY EXTENDS ACROSS SAID STEM AND IN ENGAGEMENT FOR AXIAL MOVEMENT WITH SAID SHOULDER, (H) SPRING MEANS BIASING SAID LEVER INTO ENGAGEMENT WITH SAID SHOULDER, (I) A MOVABLE ELECTRICAL CONTACT CARRIED BY SAID LEVER, (J) A STATIONARY ELECTRICAL CONTACT MOUNTED ON SAID HOUSING IN THE PIVOTAL PATH OF AND NORMALLY ENGAGING SAID MOVABLE CONTACT, (K) SAID CONTACTS BEING DIS-ENGAGED WHEN SAID PRESSURE RESPONSIVE MEMBER SENSES A PRESSURE BELOW A PREDETERMINED VALUE, (L) SECOND MEANS CONNECTED TO SAID FIRST MEANS AND MOUNTING SAID LEVER TO PIVOT TRANSVERSELY OF SAID STEM TOWARD AND AWAY FROM ENGAGEMENT WITH SAID SHOULDER, AND (M) MEANS MOUNTED IN SAID HOUSING MOVABLE TO THRUST SAID LEVER TRANSVERSELY AWAY FROM ENGAGEMENT WITH SAID SHOULDER TO PERMIT SAID CONTACTS TO ENGAGE REGARDLESS OF THE VALUE OF SAID PRESSURE. 